Launch Fuels Asia Security Concerns

By

Yuka Hayashi

Updated Dec. 13, 2012 6:49 a.m. ET

TOKYO—North Korea's successful rocket launch over Japanese territory highlights the growing security risks facing America's biggest Asian ally, and comes as the long-pacifist nation is retooling its military to face new regional threats—from Pyongyang as well as from Beijing.

U.S. officials said they believed the launch was cover for North Korea to further develop long-range missiles that could eventually carry nuclear warheads...